switch ( SubstFormat )    {    case 1:      /* no need to check glyph indices/classes used as input for these */      /* context rules since even invalid glyph indices/classes return  */      /* meaningful results                                             */      valid->extra1 = valid->lookup_count;      OTV_NEST3( ContextSubstFormat1, SubRuleSet, SubRule );      OTV_RUN( table, valid );      break;    case 2:      /* no need to check glyph indices/classes used as input for these */      /* context rules since even invalid glyph indices/classes return  */      /* meaningful results                                             */      OTV_NEST3( ContextSubstFormat2, SubClassSet, SubClassRule );      OTV_RUN( table, valid );      break;    case 3:      OTV_NEST1( ContextSubstFormat3 );      OTV_RUN( table, valid );      break;    default:      FT_INVALID_DATA;    }    OTV_EXIT;  }  /*************************************************************************/  /*************************************************************************/  /*****                                                               *****/  /*****                    GSUB LOOKUP TYPE 6                         *****/  /*****                                                               *****/  /*************************************************************************/  /*************************************************************************/  /* sets valid->extra1 (lookup count)            */  static void  otv_ChainContextSubst_validate( FT_Bytes       table,                                  OTV_Validator  valid )  {    FT_Bytes  p = table;    FT_UInt   SubstFormat;    OTV_NAME_ENTER( "ChainContextSubst" );    OTV_LIMIT_CHECK( 2 );    SubstFormat = FT_NEXT_USHORT( p );    OTV_TRACE(( " (format %d)\n", SubstFormat ));    switch ( SubstFormat )    {    case 1:      /* no need to check glyph indices/classes used as input for these */      /* context rules since even invalid glyph indices/classes return  */      /* meaningful results                                             */      valid->extra1 = valid->lookup_count;      OTV_NEST3( ChainContextSubstFormat1,                 ChainSubRuleSet, ChainSubRule );      OTV_RUN( table, valid );      break;    case 2:      /* no need to check glyph indices/classes used as input for these */      /* context rules since even invalid glyph indices/classes return  */      /* meaningful results                                             */      OTV_NEST3( ChainContextSubstFormat2,                 ChainSubClassSet, ChainSubClassRule );      OTV_RUN( table, valid );      break;    case 3:      OTV_NEST1( ChainContextSubstFormat3 );      OTV_RUN( table, valid );      break;    default:      FT_INVALID_DATA;    }    OTV_EXIT;  }  /*************************************************************************/  /*************************************************************************/  /*****                                                               *****/  /*****                    GSUB LOOKUP TYPE 7                         *****/  /*****                                                               *****/  /*************************************************************************/  /*************************************************************************/  /* uses valid->type_funcs */  static void  otv_ExtensionSubst_validate( FT_Bytes       table,                               OTV_Validator  valid )  {    FT_Bytes  p = table;    FT_UInt   SubstFormat;    OTV_NAME_ENTER( "ExtensionSubst" );    OTV_LIMIT_CHECK( 2 );    SubstFormat = FT_NEXT_USHORT( p );    OTV_TRACE(( " (format %d)\n", SubstFormat ));    switch ( SubstFormat )    {    case 1:     /* ExtensionSubstFormat1 */      {        FT_UInt            ExtensionLookupType, ExtensionOffset;        OTV_Validate_Func  validate;        OTV_LIMIT_CHECK( 6 );        ExtensionLookupType = FT_NEXT_USHORT( p );        ExtensionOffset     = FT_NEXT_ULONG( p );        if ( ExtensionLookupType == 0 ||             ExtensionLookupType == 7 ||             ExtensionLookupType > 8  )          FT_INVALID_DATA;        validate = valid->type_funcs[ExtensionLookupType - 1];        validate( table + ExtensionOffset, valid );      }      break;    default:      FT_INVALID_DATA;    }    OTV_EXIT;  }  /*************************************************************************/  /*************************************************************************/  /*****                                                               *****/  /*****                    GSUB LOOKUP TYPE 8                         *****/  /*****                                                               *****/  /*************************************************************************/  /*************************************************************************/  /* uses valid->glyph_count */  static void  otv_ReverseChainSingleSubst_validate( FT_Bytes       table,                                        OTV_Validator  valid )  {    FT_Bytes  p = table, Coverage;    FT_UInt   SubstFormat;    FT_UInt   BacktrackGlyphCount, LookaheadGlyphCount, GlyphCount;    OTV_NAME_ENTER( "ReverseChainSingleSubst" );    OTV_LIMIT_CHECK( 2 );    SubstFormat = FT_NEXT_USHORT( p );    OTV_TRACE(( " (format %d)\n", SubstFormat ));    switch ( SubstFormat )    {    case 1:     /* ReverseChainSingleSubstFormat1 */      OTV_LIMIT_CHECK( 4 );      Coverage            = table + FT_NEXT_USHORT( p );      BacktrackGlyphCount = FT_NEXT_USHORT( p );      OTV_TRACE(( " (BacktrackGlyphCount = %d)\n", BacktrackGlyphCount ));      otv_Coverage_validate( Coverage, valid );      OTV_LIMIT_CHECK( BacktrackGlyphCount * 2 + 2 );      for ( ; BacktrackGlyphCount > 0; BacktrackGlyphCount-- )        otv_Coverage_validate( table + FT_NEXT_USHORT( p ), valid );      LookaheadGlyphCount = FT_NEXT_USHORT( p );      OTV_TRACE(( " (LookaheadGlyphCount = %d)\n", LookaheadGlyphCount ));      OTV_LIMIT_CHECK( LookaheadGlyphCount * 2 + 2 );      for ( ; LookaheadGlyphCount > 0; LookaheadGlyphCount-- )        otv_Coverage_validate( table + FT_NEXT_USHORT( p ), valid );      GlyphCount = FT_NEXT_USHORT( p );      OTV_TRACE(( " (GlyphCount = %d)\n", GlyphCount ));      if ( GlyphCount != otv_Coverage_get_count( Coverage ) )        FT_INVALID_DATA;      OTV_LIMIT_CHECK( GlyphCount * 2 );      /* Substitute */      for ( ; GlyphCount > 0; GlyphCount-- )        if ( FT_NEXT_USHORT( p ) >= valid->glyph_count )          FT_INVALID_DATA;      break;    default:      FT_INVALID_DATA;    }    OTV_EXIT;  }  static const OTV_Validate_Func  otv_gsub_validate_funcs[8] =  {    otv_SingleSubst_validate,    otv_MultipleSubst_validate,    otv_AlternateSubst_validate,    otv_LigatureSubst_validate,    otv_ContextSubst_validate,    otv_ChainContextSubst_validate,    otv_ExtensionSubst_validate,    otv_ReverseChainSingleSubst_validate  };  /*************************************************************************/  /*************************************************************************/  /*****                                                               *****/  /*****                          GSUB TABLE                           *****/  /*****                                                               *****/  /*************************************************************************/  /*************************************************************************/  /* sets valid->type_count  */  /* sets valid->type_funcs  */  /* sets valid->glyph_count */  FT_LOCAL_DEF( void )  otv_GSUB_validate( FT_Bytes      table,                     FT_UInt       glyph_count,                     FT_Validator  ftvalid )  {    OTV_ValidatorRec  validrec;    OTV_Validator     valid = &validrec;    FT_Bytes          p     = table;    FT_UInt           ScriptList, FeatureList, LookupList;    valid->root = ftvalid;    FT_TRACE3(( "validating GSUB table\n" ));    OTV_INIT;    OTV_LIMIT_CHECK( 10 );    if ( FT_NEXT_ULONG( p ) != 0x10000UL )      /* Version */      FT_INVALID_DATA;    ScriptList  = FT_NEXT_USHORT( p );    FeatureList = FT_NEXT_USHORT( p );    LookupList  = FT_NEXT_USHORT( p );    valid->type_count  = 8;    valid->type_funcs  = (OTV_Validate_Func*)otv_gsub_validate_funcs;    valid->glyph_count = glyph_count;    otv_LookupList_validate( table + LookupList,                             valid );    otv_FeatureList_validate( table + FeatureList, table + LookupList,                              valid );    otv_ScriptList_validate( table + ScriptList, table + FeatureList,                             valid );    FT_TRACE4(( "\n" ));  }/* END */